Now that’s a nice lookin’ squat! 

Notice several key points:

Weight is on the heels!

Lumbar curve is good!

Bar is in the frontal plane!

You can tell that the knees track the toes!

Head is a little craned but he’s looking forward, not up!

Arms are locked out!  Yes, even with this "light" weight!!!!

"Why the overhead squat Jes?"  You ask….

The answer is simple yet complex: the overhead squat is the most difficult squat!  Your flexibility is severely tested and any weakness/laziness/tightness will be shown instantly and clearly.  Hehehe.  The other is is that as you begin to be able to load this movement your arms, neck and trunk (core) will "learn" to be as strong as your legs.  Which for any endeavor that asks you to use your arms at the same time you use your legs (pushing on things, carrying, lifting) is REALLY important 🙂

That’s why.